The seasonal biological surveys of 1971 / John C. Ayers, Samuel C. Mozley, John A. Stewart.

equivalent results: 1) Those samples examined prior to 1972 were diluted to
a known volume, mixed with a magnetic stirrer, and then subsampled with a
Henson-Stempel pipette. The 1-ml subsamples were placed in depressions on a
glass spot plate, and as many were enumerated as necessary to give counts of
several hundred for the major taxa. 2) Those samples examined in 1972 and
thereafter were subsampled with a Folsom plankton splitter, each sample being
split as many times as necessary to yield a subsample containing several
hundred of the most common taxa. Two subsamples were then counted using a
circular counting chamber, and two larger subsamples were examined for rarer
forms.
Comparability of the two subsampling methods was discussed in Part XIII,
p. 162, of our report series. In enumerating by the newer method, we have
made a number of taxonomic distinctions that had not been made previously.
The taxon "cyclopoid copepods" was broken down into adult and immature copepodids, with adults being further separated according to genus; immature
calanoid copepodids were likewise recorded separately rather than being
lumped with adults in the taxon "diaptomids"; and in the family Bosminidae,
distinction was made between the genera Bosmina and Eubosmina. In addition,
nauplii were counted in those samples examined by the more recent method. In
order that results obtained by the two counting schemes be directly comparable, we have retained the categories "total cyclopoids," "total diaptomids,"
and "total Bosminidae" throughout Table 8. In addition, column totals are
given both with and without nauplii.
At three stations (DC-6, DC-5, and DC-2) identification of adults was
carried to species.
RESULTS
Work on the zooplankton collected in 1971 was completed after we had
finished and reported the 1972 collections. Since a #10 net was used for
both collections and since monthly sampling was carried out for the first
time in 1972, this year furnishes the most useful data for comparison with
the 1971 surveys. The four 1971 dates were a happy choice, for we found four
clearly distinguishable assemblage types. A winter fauna consisting almost
exclusively of adult copepods was still present at the offshore stations in

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